Liquid crystal display and method of manufacturing the same

ABSTRACT

The present disclosure provides a liquid crystal display including: a substrate, a thin film transistor formed on the substrate, a pixel electrode connected to the thin film transistor, a roof layer formed to face the pixel electrode, a liquid crystal layer formed between the pixel electrode and the roof layer and formed of a plurality of microcavities, and a capping layer positioned on the roof layer and formed to cover a trench formed between the plurality of microcavities, in which the capping layer includes a water-soluble polymer material, a photosensitive material, and a moisture-curable adhesive.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to and the benefit of Korean PatentApplication No. 10-2015-0047704 filed in the Korean IntellectualProperty Office on Apr. 3, 2015, the entire content of which isincorporated herein by reference.

BACKGROUND

(a) Field

The present disclosure relates to a liquid crystal display and a methodof manufacturing the same.

(b) Description of the Related Art

A liquid crystal display is one of the most common types of flat paneldisplays currently in use, and includes two display panels formed offield generating electrodes such as a pixel electrode and a commonelectrode, and a liquid crystal layer interposed therebetween.

The liquid crystal display displays an image by applying a voltage tothe field generating electrode to generate an electric field on theliquid crystal layer, and thus to determine alignment of liquid crystalmolecules of the liquid crystal layer, and control polarization ofincident light.

As one of the liquid crystal displays, a technology of implementing adisplay by forming a plurality of microcavities in a pixel and fillingthem with liquid crystal has been developed. In an existing liquidcrystal display, two substrates are used, but in this technology,constituent elements may be formed on one substrate to reduce a weight,a thickness, and the like of a device.

In the process of forming the display by filling the liquid crystal inthe microcavity, the liquid crystal may be injected through a trench,and after the liquid crystal is injected, an encapsulation process maybe performed in order to close the trench and protect the entireelement.

However, there are problems in that a material used in the encapsulationprocess and the liquid crystal comes into contact with each other,causing contamination of the liquid crystal and corrosion of anelectrode formed on a substrate and the like due to remaining moisturein the material used in the encapsulation process.

The above information disclosed in this Background section is only forenhancement of understanding of the background of the invention andtherefore it may contain information that does not form the prior artthat is already known in this country to a person of ordinary skill inthe art.

SUMMARY

The present disclosure has been made in an effort to provide a liquidcrystal display where a structure is simplified and corrosion of a lowerelectrode and the like due to remaining moisture is prevented, and amethod of manufacturing the same.

An exemplary embodiment of the present disclosure provides a liquidcrystal display including: a substrate, a thin film transistor formed onthe substrate, a pixel electrode connected to the thin film transistor,a roof layer formed to face the pixel electrode, a liquid crystal layerformed between the pixel electrode and the roof layer and formed of aplurality of microcavities, and a capping layer positioned on the rooflayer and formed to cover a trench that is between the plurality ofmicrocavities, in which the capping layer includes a water-solublepolymer material, a photosensitive material, and a moisture-curableadhesive.

The moisture-curable adhesive may include at least one of a urethaneresin, a modified silicon resin, a silicon resin, and a cyanoacrylateresin.

The moisture-curable adhesive may include isocyanate.

The water-soluble polymer material may include at least one of polyvinylalcohol (PVA), methoxypolyethylene glycol, polyethylene glycol,poly(ethylene glycol) diacrylate, polyethylene glycol dimethacrylate,and polyvinylpyrrolidone.

The photosensitive material may include at least one of ammoniumdichromate, a diazo resin, a styrylpyridium group, and a stilbazoliumgroup.

The capping layer may further include a light blocking material, and thelight blocking material includes one or more of a water-soluble blackdye and a black pigment.

The water-soluble black dye may include at least one of2-naphthalenesulfonic acid, trisodium6-[(7-amino-1-hydroxy-3-sulphonato-2-naphthyl)azo]-3-[[4-[[4-amino-6 or7-sulphonatonaphthyl]azo]phenyl]azo]-4-hydroxynaphthalene-2-sulphonate,trisodium4-amino-3-[[4-[[4-[(2-amino-4-hydroxyphenyl)azo]phenyl]amino]-3-sulphonatophenyl]azo]-5-hydroxy-6-(phenylazo)naphthalene-2,7-disulphonate,and disodium4-amino-3,6-bis[[4-[(2,4-diaminophenyl)azo]phenyl]azo]-5-hydroxynaphthalene-2,7-disulphonate2,7-naphthalenedisulfonic acid.

The capping layer may be continuously formed in the entire trench.

The capping layer may be positioned in the trench, and the cappinglayers may be discontinuously formed to be spaced apart from each otherfor each microcavity.

The liquid crystal display may further include a light blocking memberpositioned in the trench and formed between the capping layer and thesubstrate.

The liquid crystal display may further include a polarizing plate formedon the capping layer and the roof layer.

The liquid crystal display may further include an overcoat layercovering the capping layer and the roof layer and covered by thepolarizing plate.

The roof layer may include a color filter.

Another exemplary embodiment provides a method of manufacturing a liquidcrystal display, including: forming a thin film transistor on asubstrate, forming a pixel electrode connected to the thin filmtransistor on the thin film transistor, forming a sacrificial layer onthe pixel electrode, forming a roof layer on the sacrificial layer,removing the sacrificial layer to form a microcavity, injecting a liquidcrystal material into the microcavity through a trench, applying acapping material to cover the roof layer and the trench, and patterningthe capping material to form a capping layer positioned in the trench,in which the capping material includes a water-soluble polymer material,a photosensitive material, and a moisture-curable adhesive.

According to the exemplary embodiment of the present invention, it ispossible to simplify a structure of a liquid crystal display by using acapping layer including a material that can perform a photo-process anda component that can adsorb moisture, and to prevent corrosion of alower electrode and the like by minimizing remaining moisture.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a top plan view illustrating a liquid crystal displayaccording to an exemplary embodiment of the inventive concept.

FIG. 2 is a cross-sectional view that is taken along line II-II of FIG.1.

FIG. 3 is a cross-sectional view that is taken along line of FIG. 1.

FIG. 4 is a top plan view illustrating disposal of a capping layer inthe liquid crystal display according to the exemplary embodiment of theinventive concept.

FIG. 5 is a top plan view illustrating disposal of the capping layer inthe liquid crystal display according to the exemplary embodiment of theinventive concept.

FIG. 6 is a cross-sectional view of the liquid crystal display accordingto the exemplary embodiment of the inventive concept.

FIG. 7 is a cross-sectional view of the liquid crystal display accordingto the exemplary embodiment of the inventive concept.

FIG. 8 is a cross-sectional view of the liquid crystal display accordingto the exemplary embodiment of the inventive concept.

FIGS. 9 and 10 are cross-sectional views illustrating a step of formingthe capping layer in a method of manufacturing the liquid crystaldisplay according to the exemplary embodiment of the inventive concept.

DETAILED DESCRIPTION OF THE EMBODIMENTS

The inventive concept will be described more fully hereinafter withreference to the accompanying drawings, in which exemplary embodimentsare shown. As those skilled in the art would realize, the describedembodiments may be modified in various different ways, all withoutdeparting from the spirit or scope of the inventive concept.

In the drawings, the thickness of layers, films, panels, regions, etc.are exaggerated for clarity. Like reference numerals designate likeelements throughout the specification. It will be understood that whenan element such as a layer, film, region, or substrate is referred to asbeing “on” another element, it can be directly on the other element orintervening elements may also be present. In contrast, when an elementis referred to as being “directly on” another element, there are nointervening elements present.

First, a display device according to an exemplary embodiment will bedescribed with reference to FIGS. 1 to 3.

FIG. 1 is a top plan view illustrating a liquid crystal displayaccording to the exemplary embodiment, FIG. 2 is a cross-sectional viewthat is taken along line II-II of FIG. 1, FIG. 3 is a cross-sectionalview that is taken along line III-III of FIG. 1, and FIG. 4 is a topplan view illustrating disposal of a capping layer in the liquid crystaldisplay according to the exemplary embodiment.

FIG. 1 illustrates a 2×2 pixel region portion that is a portion of aplurality of pixel regions, and in the liquid crystal display accordingto the exemplary embodiment, the pixel regions may be repeatedlyarranged vertically and horizontally.

First, referring to FIGS. 1 to 3, a gate line 121 and a storageelectrode line 131 are formed on a substrate 110 made of transparentglass, plastic, or the like. The gate line 121 includes a gate electrode124. The storage electrode line 131 mainly extends in a horizontaldirection and transfers a predetermined voltage such as a common voltageVcom. The storage electrode line 131 includes a pair of verticalportions 135 a extending to be substantially vertical to the gate line121, and a horizontal portion 135 b connecting ends of the pair ofvertical portions 135 a to each other. The vertical portion 135 a andthe horizontal portion 135 b have a structure surrounding a pixelelectrode 191.

A gate insulating layer 140 is formed on the gate line 121 and thestorage electrode line 131. A semiconductor layer 151 positioned on alower portion of a data line 171, and a semiconductor layer 154positioned on lower portions of source and drain electrodes 173 and 175and a channel portion of a thin film transistor Q are formed on the gateinsulating layer 140.

A plurality of ohmic contacts (not illustrated) may be formed on eachsemiconductor layer 151 and 154, and between the data line 171 and thesource/drain electrodes.

Data conductors 171, 173, and 175 including the source electrode 173,the data line 171 connected to the source electrode 173, and the drainelectrode 175 are formed on each of the semiconductor layers 151 and 154and the gate insulating layer 140.

The gate electrode 124, the source electrode 173, and the drainelectrode 175 form a thin film transistor Q together with thesemiconductor layer 154, and a channel of the thin film transistor Q isformed at the semiconductor layer portion 154 between the sourceelectrode 173 and the drain electrode 175.

A first interlayer insulating layer 180 a is formed on an exposedportion of the semiconductor layer 154, which is not covered by the dataconductors 171, 173, and 175, the source electrode 173, and the drainelectrode 175. The first interlayer insulating layer 180 a may includean inorganic material such as silicon nitride (SiNx) and silicon oxide(SiOx).

A second interlayer insulating layer 180 b and a third interlayerinsulating layer 180 c may be positioned on the first interlayerinsulating layer 180 a. The second interlayer insulating layer 180 b maybe formed of an organic material, and the third interlayer insulatinglayer 180 c may include an inorganic material such as silicon nitride(SiNx) and silicon oxide (SiOx). The second interlayer insulating layer180 b may be formed of the organic material to reduce or remove aprocess step. One or two layers of the first interlayer insulating layer180 a, the second interlayer insulating layer 180 b, and the thirdinterlayer insulating layer 180 c may be omitted.

A contact hole 185 may be formed through the first interlayer insulatinglayer 180 a, the second interlayer insulating layer 180 b, and the thirdinterlayer insulating layer 180 c. The drain electrode 175 and the pixelelectrode 191 positioned on the third interlayer insulating layer 180 cmay be electrically and physically connected through the contact hole185. Hereinafter, the pixel electrode 191 will be specificallydescribed.

The pixel electrode 191 may be made of a transparent conductive materialsuch as ITO or IZO.

A whole shape of the pixel electrode 191 is a quadrangle, and the pixelelectrode 191 includes a cross-shaped stem portion formed of ahorizontal stem portion 191 a and a vertical stem portion 191 b crossingthe horizontal stem portion 191 a. Further, the pixel electrode 191 isdivided into four sub-regions by the horizontal stem portion 191 a andthe vertical stem portion 191 b, and each sub-region includes aplurality of fine branch portions 191 c. Further, in the presentexemplary embodiment, an outskirt stem portion 191 d connecting the finebranch portions 191 c may be further included at left and rightoutskirts of the pixel electrode 191. In the present exemplaryembodiment, the outskirt stem portions 191 d are positioned at the leftand right outskirts of the pixel electrode 191, but may be positioned toextend to an upper portion or a lower portion of the pixel electrode191.

The fine branch portion 191 c of the pixel electrode 191 forms an angleof about 40° to 45° with the gate line 121 or the horizontal stemportion 191 a. Further, the fine branch portions 191 c of the twoadjacent sub-regions may be orthogonal to each other. Further, a widthof the fine branch portion may be gradually increased, and intervalsbetween the fine branch portions 191 c may be different from each other.

The pixel electrode 191 includes an extension portion 197 connected at alower end of the vertical stem portion 191 b and having an area that iswider than that of the vertical stem portion 191 b, is physically andelectrically connected through the contact hole 185 to the drainelectrode 175 at the extension portion 197, and receives a data voltagefrom the drain electrode 175.

The description relating to the thin film transistor Q and the pixelelectrode 191 is an example, and a structure of the thin film transistorQ and a design of the pixel electrode 191 may be modified in order toimprove lateral surface visibility.

A lower alignment layer 11 is formed on the pixel electrode 191, and thelower alignment layer 11 may be a vertical alignment layer. The loweralignment layer 11 may be formed to include at least one of materialsgenerally used as a liquid crystal alignment layer, such as polyamicacid, polysiloxane, or polyimide. Further, the lower alignment layer 11may be a photo-alignment layer.

An upper alignment layer 21 is positioned on a portion facing the loweralignment layer 11, and a plurality of microcavities 305 are formedbetween the lower alignment layer 11 and the upper alignment layer 21. Aliquid crystal material including a liquid crystal molecule 310 isinjected into the microcavity 305, and the microcavity 305 has an inputportion 307. The microcavity 305 may be formed in a column direction ofthe pixel electrode 191, in other words, a vertical direction. In thepresent exemplary embodiment, an alignment material forming thealignment layers 11 and 21 and a liquid crystal material including theliquid crystal molecule 310 may be injected into the microcavity 305 byusing capillary force. In the present exemplary embodiment, the loweralignment layer 11 and the upper alignment layer 21 are classifiedaccording to a position, and as illustrated in FIG. 3, may be connectedto each other. The lower alignment layer 11 and the upper alignmentlayer 21 may be simultaneously formed.

The microcavity 305 is divided in the vertical direction by a pluralityof trenches 307FP positioned at a portion overlapping with the gate line121 to form the plurality of microcavities 305, and the plurality ofmicrocavities 305 may be formed in the column direction of the pixelelectrode 191, in other words, the vertical direction. Further, themicrocavity 305 is divided in a horizontal direction by a partition wallportion PWP as will be described later to form the plurality ofmicrocavities 305, and the plurality of microcavities 305 may be formedin a row direction of the pixel electrode 191, in other words, in ahorizontal direction in which the gate line 121 extends. Each of themicrocavities 305 formed in plural may correspond to one or two or morepixel regions, and the pixel region may correspond to a regiondisplaying a screen.

A common electrode 270 and a lower insulating layer 350 are positionedon the upper alignment layer 21. The common electrode 270 receives acommon voltage and forms an electric field together with the pixelelectrode 191 to which a data voltage is applied to determine aninclination direction of the liquid crystal molecule 310 positioned inthe microcavity 305 between the two electrodes. The common electrode 270and the pixel electrode 191 form a capacitor to maintain the appliedvoltage even after the thin film transistor Q is turned-off.

The lower insulating layer 350 may be formed of silicon nitride (SiNx)or silicon oxide (SiOx).

Formation of the common electrode 270 in an upper end of the microcavity305 is described in the present exemplary embodiment, but unlike this,the common electrode 270 can be formed in a lower portion of themicrocavity 305 to drive a liquid crystal according to a coplanarelectrode mode.

In the present exemplary embodiment, a roof layer 230 is positioned onthe lower insulating layer 350, and may be formed of an organicmaterial. The microcavity 305 is formed beneath the roof layer 230, andthe roof layer 230 may be hardened by a curing process to maintain ashape of the microcavity 305. That is, the roof layer 230 is formed tobe spaced apart from the pixel electrode 191 while the microcavity 305is interposed between the roof layer and the pixel electrode 191.

The roof layer 230 is formed in an extension direction of the data line171. In this case, in the trench 307FP, the roof layer 230 is removed toform the input portion 307 corresponding to a portion where an alignmentmaterial or a liquid crystal material is injected into the microcavity305.

The roof layers 230 on the microcavity 305 may meet each other at aportion overlapping with the data line 171 to form the partition wallportion PWP, and the partition wall portion PWP may serve tocompartmentalize the microcavities 305. That is, the partition wallportion PWP fills the space between the microcavities 305 adjacent in ahorizontal direction. In the embodiment of FIG. 3, the partition wallportion PWP is formed in a structure where the space between themicrocavities 305 is completely filled. This is not necessarily alimitation of the inventive concept, and a structure where less than allof the space is filled is contemplated. The partition wall portion PWPmay be formed in an extension direction of the data line 171.

In some embodiments, the roof layer 230 may be formed of a color filter.In this case, the color filter may form the partition wall portion PWP,and an interface of the color filters adjacent to each other may bepositioned at a portion corresponding to the partition wall portion PWP,and in this case, the adjacent color filters may overlap with eachother.

An upper insulating layer 370 is positioned on the roof layer 230. Theupper insulating layer 370 may be formed of silicon nitride (SiNx) orsilicon oxide (SiOx). As illustrated in FIG. 2, the upper insulatinglayer 370 may cover a lateral surface portion of the roof layer 230.

Next, referring to FIGS. 2 and 4, a capping layer 390 is positioned inthe trench 307FP, and covers the input portion 307 of the microcavity305 exposed by the trench 307FP. The capping layer 390 may come intocontact with the liquid crystal material positioned in the microcavity305. Specifically, the capping layer 390 is continuously positionedalong the trench 307FP. In some embodiments, the capping layer 390 iscontinuously disposed along the trench 307FP but not disposed on themicrocavity 305 in the pixel region.

The capping layer 390 according to the present exemplary embodimentincludes a water-soluble polymer material, a photosensitive material,and a moisture-curable adhesive.

In the present exemplary embodiment, the water-soluble polymer materialmay be polyvinyl alcohol represented by the following ChemicalFormula 1. Further, the water-soluble polymer material according to thepresent exemplary embodiment may include at least one ofmethoxypolyethylene glycol, polyethylene glycol, poly(ethylene glycol)diacrylate, polyethylene glycol dimethacrylate, andpolyvinylpyrrolidone. In Chemical Formula 1, n represents the number ofrepeating units and may be a natural number.

In the present exemplary embodiment, the photosensitive material mayinclude at least one of ammonium dichromate, a diazo resin, astyrylpyridium group, and a stilbazolium group. The capping layer 390may include the photosensitive material to have a property where aphoto-process is feasible.

In the present exemplary embodiment, the capping layer 390 may includethe moisture-curable adhesive, and the moisture-curable adhesive meansan adhesive initiating polymerization by moisture in the air or moistureattached to a surface of an object to be attached to perform curing.

The moisture-curable adhesive according to the present exemplaryembodiment may include isocyanate, but is not limited thereto as long asthe adhesive is a moisture-curable adhesive, and for example, themoisture-curable adhesive may be an adhesive including at least one of aurethane resin, a modified silicon resin, a silicon resin, and acyanoacrylate resin.

The capping layer 390 according to the present exemplary embodimentincludes, as described above, the water-soluble polymer material, andthus even though the capping layer 390 is formed, remaining moisture mayexist in the capping layer 390. In the case where a separate process isperformed in order to remove moisture remaining in the capping layer390, there is a drawback in views of a separate process time or cost,and moreover, due to remaining moisture, corrosion of the electrode suchas the pixel electrode 191 formed in the lower portion of the cappinglayer 390 may occur.

Therefore, the capping layer 390 according to the present exemplaryembodiment may include the moisture-curable adhesive initiatingpolymerization by moisture to remove remaining moisture without aseparate process of removing remaining moisture in a process of formingthe capping layer 390 and prevent corrosion of the electrode such as thepixel electrode 191 formed in the lower portion.

Further, the capping layer 390 according to the exemplary embodiment mayfurther include a light blocking material.

In the present exemplary embodiment, the light blocking material mayinclude a water-soluble black dye or a black pigment. The water-solubleblack dye may be dissolved in a capping material forming the cappinglayer 390, and the black pigment may exist in a form where the blackpigment is dispersed in the capping material.

The water-soluble black dye according to the present exemplaryembodiment may include at least one of 2-naphthalenesulfonic acid,trisodium6-[(7-amino-1-hydroxy-3-sulphonato-2-naphthyl)azo]-3-[[4-[[4-amino-6 or7-sulphonatonaphthyl]azo]phenyl]azo]-4-hydroxynaphthalene-2-sulphonate,trisodium4-amino-3-[[4-[[4-[(2-amino-4-hydroxyphenyl)azo]phenyl]amino]-3-sulphonatophenyl]azo]-5-hydroxy-6-(phenylazo)naphthalene-2,7-disulphonate,and disodium4-amino-3,6-bis[[4-[(2,4-diaminophenyl)azo]phenyl]azo]-5-hydroxynaphthalene-2,7-disulphonate2,7-naphthalenedisulfonic acid.

In the case where the capping layer 390 includes the light blockingmaterial, the capping layer 390 may serve as a light blocking member forblocking light leakage. In this case, a separate process for forming thelight blocking member may be omitted.

The aforementioned structure of the liquid crystal display according tothe present exemplary embodiment is just an example, and numerousvariations are feasible. For example, disposal forms of the microcavity305, the trench 307FP, and the partition wall portion PWP can bechanged, the roof layers 230 may be connected to each other in thetrench 307FP, and a portion of each roof layer 230 may be formed to beseparated from the substrate 110 at the partition wall portion PWP andthus connect the adjacent microcavities 305 to each other.

Then, the liquid crystal display according to the exemplary embodimentwill be described with reference to FIG. 5.

FIG. 5 is a top plan view illustrating disposal of the capping layer inthe liquid crystal display according to the exemplary embodiment.

Since the exemplary embodiment illustrated in FIG. 5 is the same as theexemplary embodiment illustrated in FIGS. 1 to 3 with the exception of aplanar position of the capping layer 390, an overlapping descriptionthereof will be omitted.

As illustrated in FIG. 5, the capping layer 390 of the liquid crystaldisplay according to the exemplary embodiment is positioned in thedirection in which the gate line 121 extends, in the trench 307FP.However, the capping layers may be spaced apart from each other in anisland form for each microcavity 305. That is, in the trench 307FP,which corresponds to the partition wall portion PWP, at a position wherethe data line 171 is formed, the capping layer 390 may not be formed.

Next, the liquid crystal displays according to the exemplary embodimentwill be described with reference to FIGS. 6 and 7.

FIG. 6 is a cross-sectional view of the liquid crystal display accordingto the exemplary embodiment, and FIG. 7 is a cross-sectional view of theliquid crystal display according to the exemplary embodiment.

Since the exemplary embodiment illustrated in FIGS. 6 and 7 is the sameas the exemplary embodiment illustrated in FIGS. 1 to 3, except whetheran overcoat layer 395 and a polarizing plate 400 exist or not, anoverlapping description thereof will be omitted.

First, as illustrated in FIG. 6, the liquid crystal display according tothe exemplary embodiment may further include the overcoat layer 395formed of an inorganic layer or an organic layer on an entire surface ofthe substrate 110 including the capping layer 390, and the polarizingplate 400 formed on the overcoat layer 395. The overcoat layer 395serves to protect the liquid crystal molecule 310 injected into themicrocavity 305 from an external impact and planarize the layer.Further, the overcoat layer 395 may serve to block external moisture andoxygen.

Unlike this, as illustrated in FIG. 7, the liquid crystal display mayfurther include only the polarizing plate 400 on the entire surface ofthe substrate including the capping layer 390 without the overcoat layer395.

Next, the liquid crystal display according to the exemplary embodimentwill be described with reference to FIG. 8.

FIG. 8 is a cross-sectional view of the liquid crystal display accordingto the exemplary embodiment.

Since the exemplary embodiment illustrated in FIG. 8 is the same as theexemplary embodiment illustrated in FIGS. 1 to 3, except whether a lightblocking member 220 exists or not, an overlapping description thereofwill be omitted.

As illustrated in FIG. 8, in the liquid crystal display according to theexemplary embodiment, the capping layer 390 does not include the lightblocking material, and in the trench 307FP as a region between theadjacent microcavities 305, the light blocking member 220 is formed andmay be positioned on the pixel electrode 191 and a third interlayerinsulating layer 180 c not covered by the pixel electrode. The lightblocking member 220 may be formed on a boundary portion of a pixel andthe thin film transistor Q to prevent light leakage.

The light blocking member 220 extends upwardly and downwardly along thegate line 121, and may include a horizontal light blocking member 220covering a region where the thin film transistor Q and the like arepositioned and a vertical light blocking member 220 extending along thedata line 171. That is, the horizontal light blocking member 220 may beformed in the trench 307FP, and the vertical light blocking member 220may be formed at a position corresponding to the partition wall portionPWP.

Hereinafter, a method of manufacturing the liquid crystal displayaccording to the exemplary embodiment will be described in brief withreference to FIGS. 9 and 10.

FIGS. 9 and 10 are cross-sectional views illustrating the process offorming the capping layer in a method of manufacturing the liquidcrystal display according to the exemplary embodiment.

First, referring to FIG. 9, in the method of manufacturing the liquidcrystal display according to the exemplary embodiment, a thin filmtransistor Q is formed on a substrate 110.

Next, a first interlayer insulating layer 180 a, a second interlayerinsulating layer 180 b, and a third interlayer insulating layer 180 care formed on the thin film transistor Q, and a contact hole 185 isformed therethrough. Thereafter, a pixel electrode 191 is formed on thethird interlayer insulating layer 180 c, and the pixel electrode 191 iselectrically and physically connected to a drain electrode 175 of thethin film transistor Q through the contact hole 185. The pixel electrode191 may be formed of a transparent conductor such as ITO or IZO.

A sacrificial layer (not illustrated) including an opening portion (notillustrated) is formed in a direction that is parallel to a data line171 on the pixel electrode 191. In the opening portion, a roof layer 230may be filled in a subsequent process to form a partition wall portionPWP. The sacrificial layer may be formed of a photoresist material or anorganic material excluding the photoresist material.

A common electrode 270 and a lower insulating layer 350 are sequentiallyformed on the sacrificial layer. The common electrode 270 may be formedof a transparent conductor such as ITO or IZO, and the lower insulatinglayer 350 may be formed of silicon nitride (SiNx) or silicon oxide(SiO₂). The roof layer 230 and the upper insulating layer 370 aresequentially formed on the lower insulating layer 350. The roof layer230 may be formed of a color filter. The upper insulating layer 370 maybe formed of silicon nitride (SiNx) or silicon oxide (SiO₂). Herein, theroof layer 230 may be removed at a portion where a trench 307FP will beformed by a patterning process or an exposure/developing process.

The upper insulating layer 370, the lower insulating layer 350, and thecommon electrode 270 positioned to correspond to the trench 307FP aresequentially patterned to expose the sacrificial layer, and thesacrificial layer is removed through the trench 307FP by oxygen (O2)ashing treatment, a wet etching method, or the like. In this case, amicrocavity 305 having an input portion 307 is formed. The microcavity305 is in a hollow space state because the sacrificial layer is removed.

An alignment material is injected through the input portion 307 to formalignment layers 11 and 21 on the pixel electrode 191 and the commonelectrode 270, and a liquid crystal material including a liquid crystal310 is injected through the input portion 307 into the microcavity 305by using an inkjet method and the like.

If the liquid crystal material is injected, since the liquid crystalmaterial may be exposed to the outside by the trench 307FP, a cappingmaterial 390 m is applied to cover the trench 307FP.

Herein, the used capping material 390 m may include a material includedin the aforementioned capping layer 390.

Next, as illustrated in FIG. 9, a pixel region corresponding to aplurality of microcavities 305 is covered by a mask to perform exposure.That is, an entire surface of the substrate 110 excluding the trench307FP may be covered by the mask to perform exposure.

Thereafter, as illustrated in FIG. 10, the mask is removed and thecapping material 390 m positioned in the pixel region is removed througha developing process to form the capping layer 390 positioned along thetrench 307FP.

In the present exemplary embodiment, patterning is performed in anegative photoresist form in which a portion not receiving light isremoved during exposure. However, unlike this, the capping material maybe formed of a material having a positive photoresist property, and inthis case, patterning may be performed by using a mask that is a reverseimage of the aforementioned mask.

According to the aforementioned exemplary embodiments, the inventiveconcept allows a structure to be simplified by using a capping layerincluding a material that can perform a photo-process and a componentthat can adsorb moisture and to prevent corrosion of a lower electrodeand the like by remaining moisture.

While this inventive concept has been described in connection with whatis presently considered to be practical exemplary embodiments, it is tobe understood that the inventive concept is not limited to the disclosedembodiments, but, on the contrary, is intended to cover variousmodifications and equivalent arrangements included within the spirit andscope of the appended claims.

<Description of symbols>  3: Liquid crystal layer 230: Roof layer 307FP:Trench 310: Liquid crystal molecule 305: Microcavity 307: Input portion350: Lower insulating layer 370: Upper insulating layer 390: Cappinglayer

What is claimed is:
 1. A liquid crystal display comprising: a substrate,a thin film transistor formed on the substrate, a pixel electrodeconnected to the thin film transistor, a roof layer formed to face thepixel electrode, a liquid crystal layer formed between the pixelelectrode and the roof layer and formed of a plurality of microcavities,and a capping layer positioned on the roof layer and formed to cover atrench that is between the plurality of microcavities, wherein thecapping layer includes a water-soluble polymer material, aphotosensitive material, and a moisture-curable adhesive.
 2. The liquidcrystal display of claim 1, wherein: the moisture-curable adhesiveincludes at least one of a urethane resin, a modified silicon resin, asilicon resin, and a cyanoacrylate resin.
 3. The liquid crystal displayof claim 2, wherein: the moisture-curable adhesive includes isocyanate.4. The liquid crystal display of claim 2, wherein: the water-solublepolymer material includes at least one of polyvinyl alcohol (PVA),methoxypolyethylene glycol, polyethylene glycol, poly(ethylene glycol)diacrylate, polyethylene glycol dimethacrylate, andpolyvinylpyrrolidone.
 5. The liquid crystal display of claim 2, wherein:the photosensitive material includes at least one of ammoniumdichromate, a diazo resin, a styrylpyridium group, and a stilbazoliumgroup.
 6. The liquid crystal display of claim 2, wherein: the cappinglayer further includes a light blocking material, and the light blockingmaterial includes one or more of a water-soluble black dye and a blackpigment.
 7. The liquid crystal display of claim 6, wherein: thewater-soluble black dye includes at least one of 2-naphthalenesulfonicacid, trisodium6-[(7-amino-1-hydroxy-3-sulphonato-2-naphthyl)azo]-3-[[4-[[4-amino-6 or7-sulphonatonaphthyl]azo]phenyl]azo]-4-hydroxynaphthalene-2-sulphonate,trisodium,4-amino-3-[[4-[[4-[(2-amino-4-hydroxyphenyl)azo]phenyl]amino]-3-sulphonatophenyl]azo]-5-hydroxy-6-(phenylazo)naphthalene-2,7-disulphonate,and disodium4-amino-3,6-bis[[4-[(2,4-diaminophenyl)azo]phenyl]azo]-5-hydroxynaphthalene-2,7-disulphonate2,7-naphthalenedisulfonic acid.
 8. The liquid crystal display of claim6, wherein: the capping layer is continuously formed in the entiretrench.
 9. The liquid crystal display of claim 6, wherein: the cappinglayer is positioned in the trench, and the capping layers arediscontinuously formed to be spaced apart from each other for eachmicrocavity.
 10. The liquid crystal display of claim 1, furthercomprising: a light blocking member positioned in the trench and formedbetween the capping layer and the substrate.
 11. The liquid crystaldisplay of claim 1, further comprising: a polarizing plate formed on thecapping layer and the roof layer.
 12. The liquid crystal display ofclaim 11, further comprising: an overcoat layer covering the cappinglayer and the roof layer and covered by the polarizing plate.
 13. Theliquid crystal display of claim 1, wherein: the roof layer includes acolor filter.
 14. A method of manufacturing a liquid crystal display,comprising: forming a thin film transistor on a substrate, forming apixel electrode connected to the thin film transistor on the thin filmtransistor, forming a sacrificial layer on the pixel electrode, forminga roof layer on the sacrificial layer, removing the sacrificial layer toform a microcavity, injecting a liquid crystal material into themicrocavity through a trench, applying a capping material to cover theroof layer and the trench, and patterning the capping material to form acapping layer positioned in the trench, wherein the capping materialincludes a water-soluble polymer material, a photosensitive material,and a moisture-curable adhesive.
 15. The method of claim 14, wherein:the moisture-curable adhesive includes at least one of a urethane resin,a modified silicon resin, a silicon resin, and a cyanoacrylate resin.16. The method of claim 15, wherein: the moisture-curable adhesiveincludes isocyanate.
 17. The method of claim 15, wherein: thewater-soluble polymer material includes at least one of polyvinylalcohol (PVA), methoxypolyethylene glycol, polyethylene glycol,poly(ethylene glycol) diacrylate, polyethylene glycol dimethacrylate,and polyvinylpyrrolidone.
 18. The method of claim 15, wherein: thephotosensitive material includes at least one of ammonium dichromate, adiazo resin, a styrylpyridium group, and a stilbazolium group.
 19. Themethod of claim 15, wherein: the capping layer further includes a lightblocking material, and the light blocking material includes one or moreof a water-soluble black dye and a black pigment.